Microspeakers can overheat and break if not monitored and regulated. This monitoringis usually done by adding a pilot tone that introduces energy to the signal.A problem with this approach is the slow update rate of the temperature estimate.This in combination with a fast temperature rise could result in an audible regulationof the input. By simulating the voice coil temperature these problems couldbe mitigated. In this thesis, two existing grey box models and one novel black boxmodel are estimated for different speakers and evaluated using different signals.The results are promising and indicate that all models can estimate the voice coiltemperature with a mean error below one degree. The tests show that a correctinitialization of the model is crucial. Therefore the suggestion to Cirrus Logic,who hosted this thesis project, is to combine a feedforward model with eithertemperature sensor data from the mobile device or a pilot tone. / Mikrohögtalare kan överhettas och gå sönder ifall temperaturen inte övervakasoch regleras vid behov. Denna övervakning sker med hjälp av en pilotton somtillför energi till högtalarens insignal. Ett problem med denna lösning är att övervakningenär relativt långsam. Detta gör att en snabb temperaturökning kan geen oönskad hörbar reglering av insignalen. Genom att modellera spolens temperaturkan detta problem hanteras. I detta examensarbete tas två fysikaliska modelleroch en konfektionsmodell fram och testas på olika högtalare och signaler.Resultaten är lovande och visar att alla modeller kan skatta spoltemperaturenmed ett medelfel under en grad. Utvärderingen visar att initiering av modellensstarttemperatur är viktig. Därför är förslaget till Cirrus Logic att kombinera en simuleringsmodellsom initieras med antingen temperatursensordata från mobileneller med hjälp av en pilotton.

No description available.

In the past the machinery used in punching of flexible printed circuit boards(FPCBs), it used mostly the rotary motor as the power source in the mechanism design. To transfer rotary motion to linear motion need a succession of mechanical conversion components, in order to achieve the purpose of linear output. However these mechanical parts for transforming bring some unavoidable problems such as the machinery itself huge volume, backlash and friction which created during the action process, all have harmful influences on the system dynamic performance and precision. Voice coil actuator has direct-drive output, high response and high thrust force these characteristics, therefore this research apply voice coil actuator to the punching of flexible printed circuit boards. For present industry, S-curve velocity profile is often used in point-to-point displacement intermittent action applications, due to its jerk-limited characteristic for reducing vibration and raising precision. Then integrating plans of S-curve velocity profile with voice coil actuator based on punching characters, to analyze the whole system dynamic performance in such a vertical linear output application. Then generalizing the dependence of influence factors of punching quality and motion characteristics of punching mechanism through experimental results. The achievement of this research could provide references for some related designers using similar linear actuators in vertical linear output applications.

The position control has played an important role in high-tech industries. For example, we hope the control performance fast and precisely in the biomedical industry or high-speed precision machinery. However, the high-precision positioning platform will encounter backlash, friction, hysteresis ... and so on. Therefore, this paper will use the linear voice coil motor to drive single-axis flexure mechanism, to solve the nonlinear problem unnecessarily. Then, the quantized current regulator has been reached by high efficiency robust frequency control and to design with a low-pass filter of the interference within the system parameter estimation to reduce the impact of changes in items, and then by the simulation test analysis showed that the proposed hybrid control method has simultaneous control of voice coil motor current and the flexure mechanism targeting the advantages of location, and the use of traditional pulse-width modulation of the PI current controller with integral type of smooth position control mode, respectively quantized current regulator and the disturbance estimator to do a comparative analysis of simulation . Finally the use analogies full the bridge electric circuit, several logic and the operational amplifier realizes the quantification current regulator.

In this master thesis, a new method for estimating the position of the moving parts of avoice coil is presented. Instead of using a position sensor the method exploits the connectionbetween the position and the inductance of the voice coil. This is done by superpositioning a small sine voltage signal and the voice coil voltage control signal. By measuring thevoltage and current and using the fourier transform, the impedance and phase difference iscalculated which are used to compute the inductance. A medical ventilator (also known as a respirator) concept is developed with a control systemwhich takes the expiratory pressure from a higher to a lower level. The position estimationalgorithm is then used in an attempt to improve the pressure control. The result is a slightlymore stable control system. The master thesis is conducted at Maquet Critical Care (MCC) in Solna, Sweden. MCC is amedical technology company working with high performance medical ventilators. The longterm goal of this work is to develop a ventilator which is more comfortable for the patient.

There is a large number of measurement techniques that is used for a surface inspection and a characterization of different types of materials. One of these techniques is a contact potential difference (CPD) scanning technique. In this project a non-vibrating contact potential difference (nvCPD) method is utilized to measure a work function and a topographical structure of a sample surface. A sample is mounted on a spindle that rotates at high speed. A nvCPD sensor detects work-function variations during movement above the sample surface. There are certain factors that create difficulties during the measurement process. A nonplanar sample surface, the spindle wobble and an incline of a mounted sample impede the safe (without impacting the surface) scanning at a close distance. The goal of this thesis was to implement a height sensor as a feedback device to dynamically control and adjust a CPD sensor flying height. Since a CPD signal is inversely proportional to the flying height, minimization of this height will enhance the signal magnitude, the signal-to-noise ratio and the resolution of measurements.

No description available.

A percussion performance by a skilled musician will often extend beyond a written score in terms of expressiveness. This assertion is clearly evident when comparing a human performance with one that has been rendered by some form of automaton that expressly follows a transcription. Although music notation enforces a significant set of constraints, it is the responsibility of the performer to interpret the piece and “bring it to life” in the context of the composition, style, and perhaps with a historical perspective. In this sense, the sheet music serves as a general guideline upon which to build a credible performance that can carry with it a myriad of subtle nuances. Variations in such attributes as timing, dynamics, and timbre all contribute to the quality of the performance that will make it unique within a population of musicians. The ultimate goal of this research is to gain a greater understanding of these subtle nuances, while simultaneously developing a set of stochastic motion models that can similarly approximate minute variations in multiple dimensions on a purpose-built robot. Live or recorded motion data, and algorithmic models will drive an articulated robust multi-axis mechatronic system that can render a unique and audibly pleasing performance that is comparable to its human counterpart using the same percussion instruments. By utilizing a non-invasive and flexible design, the robot can use any type of drum along with different types of striking implements to achieve an acoustic richness that would be hard if not impossible to capture by sampling or sound synthesis. The flow of this thesis will follow the course of this research by introducing high-level topics and providing an overview of related work. Next, a systematic method for gesture acquisition of a set of well-defined percussion scores will be introduced, followed by an analysis that will be used to derive a set of requirements for motion control and its associated electromechanical subsystems. A detailed multidiscipline engineering effort will be described that culminates in a robotic platform design within which the stochastic motion models can be utilized. An analysis will be performed to evaluate the characteristics of the robotic renderings when compared to human reference performances. Finally, this thesis will conclude by highlighting a set of contributions as well as topics that can be pursued in the future to advance percussion robotics. / Graduate / 2019-12-10

Mechanical ventilators are devices in critical care to assist breathing in case of expiratory dysfunction. The expiratory valve is a critical component to the ventilator as it controls the pressure in the patient’s lungs. The design process of a new expiratory valve assembly is a time consuming one due to the wide range of possible design solutions both the voice-coil actuators and membrane valves typically used in ventilators. This thesis evaluates the possibility of creating and using analytical models for model based development to speed up the early design phases of a expiratory valve assembly. The main components, voice-coil actuator and membrane valve are modelled separately and experimentally verified. A complete expiratory system model and hardware-in-the-loop test setup are constructed in order to explore how well can the dynamic properties and control performance of valve assembly be predicted. Finally various questions in the valve assembly design are explored and a new design is proposed to demonstrate the capabilities of the model based approach. The resulting voice-coil and membrane valve models can be considered accurate enough for fast exploration of the design space, as an error rate below 10% is reached without manual tuning for each design. / Mekaniska ventilatorer är en utrustning inom intensivvården för assisterad andning för patienter med nedsatt andningsförmåga. Utandningsventilen är en kritisk komponent till ventilatorn då den kontrollerar lungtrycket hos patienten. Design processen för en ny utandningsventil är en tidskrävande process mycket på grund av den mängd olika design möjligheter som kan utforskas för både talspole aktuatorn samt membran ventilen som oftast används i ventilatorerna. I detta examensarbete utforskades möjligheterna till att skapa och använda analytiska modeller för modellbaserad utveckling för att accelerera de tidiga design stadierna för en utandningsventil. Huvudkomponenterna, talspole aktuatorn och membran ventilen är modellerade separat och experimentellt verifierade. En fullständig modell för hela utandningssystemet samt en hardware-in-the-loop test plattform är konstruerad för att utforska hur väl de dynamiska egenskaperna samt kontroll prestandan för en utandningsventil kan prediceras. Slutligen utforskas diverse frågor angående ventil designen och en ny design föreslås för att demonstrera möjligheterna med en modellbaserad metod. Den slutliga modellen för både talspole aktuatorn och membran ventilen kan betraktas som tillräcklig precisa för snabb utforskning inom de olika design möjligheterna, då en felprocent under 10% är uppnådd utan manuell finjustering för varje design.

This thesis research is concerned with the exploration, design, and validation of novel haptic technologies and signals that feel natural and meaningful in a calm and pleasant way. Our ultimate goal is to expand the possibilities of human-machine interaction by developing a single tactile display and a set of signals through a systematic design approach. It is generally a challenge to evoke a broad range of emotions with vibrotactile stimulation, especially at low signal intensities. During the first part of this thesis research, three types of prototypes were developed and explored using novel haptic technologies. The first was a circular array braille display consisting of eight small six-pin braille modules. The forty-eight pins were arranged in a circular shape to deliver circular tactile information such as time and direction. The second was a braille stick consisting of sixteen six-pin braille modules arranged in a row. The entire display could be easily grasped in the hand so that tactile information can be easily accessible. The third was a 3-by-3 electroactive polymer actuator array driven at high voltages that gives a subtle “tapping” feel on the skin. However, each of the three prototypes suffered from a limited range of expression and was not pursued further.<br> After the initial prototyping efforts, a 2-by-2 vibrotactile display, the palmScape, was conceived and developed. Custom-designed stimulation patterns based on natural phenomena that feel calm and pleasant were designed and implemented with the palmScape. We use text labels to set the context for the vibrotactile icons that attempt to capture and expresses natural metaphors through variations in signal amplitude, frequency, duration, rhythm, modulation, spatial extent, as well as slow movements. Fourteen participants evaluated twenty vibrotactile icons by rating the perceived valence and arousal levels. The twenty stimuli included sixteen custom-designed vibrotactile icons from this thesis research and four reference patterns from two published studies. The results show that our custom-designed patterns were rated at higher valence levels than the corresponding reference signals at similar arousal ratings. Five of the sixteen vibrotactile icons from this research occupied the fourth quadrant of the valence-arousal space that corresponds to calm and pleasant signals. These findings support the validity of the palmScape display and our signal design approach for achieving a calm and pleasant experience and the possibility of reaching a broader range of expressiveness with vibrotactile signals.<br> Future studies will continue with the design of signals that can express a broader range of metaphors and emotions through the palmScape, and build an emotional evaluation database that can be combined with other modalities. Our work can be further expanded to support an immersive experience with naturalistic-feeling vibrotactile effects and broaden the expressiveness of human-computer interfaces in media consumption, gaming, and other communicative application domains.